Humidifier preparatory solution of formaldehyde, polyoxypropylene glycol-ethylene oxide condensation product and water and method of use

ABSTRACT

The means for humidifying a vapor includes a humidifier having a reservoir and a wick therein. A preparatory solution adapted to be added to water within the reservoir contains between 69 percent and 94 percent by weight of water approximately 1 percent by weight of a 37 percent solution of formaldehyde, and between 5 percent and 30 percent by weight of a condensation product selected from the group of polyoxypropylene glycols condensed with ethylene oxide to form a molecule consisting of (A) a polyoxypropylene portion and (B) a polyoxyethylene portion. The ratio of the molecular weight of (A) to the percentage by weight of (B) in the total molecule is one from the group consisting of 1,501-1,800 : 80, 1,501-1,800 : 40; 1,501-1,800 : 20, and 2,1012,500 : 80.

United States Patent Roberts 51 or. 2, W72

Inventor: Eugene C. Roberts, 1 Sunnyside Drive,

Belleville, 111. 62223 Filed: Oct. 1, 1969 Appl. No.: 862,964

US. Cl ..252/180, 210/58, 210/59, 239/44, 252/82 Int. Cl. .C02b 5/06 Field oiSearch ..252/176, 180,178, 82; 210/41, 210/50, 58, 59, 60; 239/44; 260/615, 875

References Cited UNITED STATES PATENTS 3/1967 Rait ..252/194 X Assistant Examiner-M. E. McCamish Attorney-John D. Pope, 111

[5 7] ABSTRACT The means for humidifying a vapor includes a humidifier having a reservoir and a wick therein. A preparatory solution adapted to be added to water within the reservoir contains between 69 percent and 94 percent by weight of water approximately 1 percent by weight of a 37 percent solution of formaldehyde, and between 5 percent and 30 percent by weight of a condensation product selected from the group of polyoxypropylene glycols condensed with ethylene oxide to form a molecule consisting of (A) a polyoxypropylene portion and (B) a polyoxyethylene portion. The ratio of the molecular weight of (A) to the percentage by weight of (B) in the total molecule is one from the group consisting of 1,501-1 ,800 80, l,50l-1,800 40; 1,501-1,800 20, and 2,l0l-2,500 80.

7 Claims, No Drawings HUMIDIFIER PREPARATORY SOLUTION OF FORMALDEHYDE, POLYOXYPROPYLENE GLYCOL- ETHYLENE OXIDE CONDENSATION PRODUCT AND WATER AND METHOD OF USE One problem encountered in the use of humidifiers has,

been the accumulation of hard water salts on the evaporating surfaces of the wicklike members. As the humidifier is used over an extended period of time the concentration of the hard water salts in the reservoir increases as a result of the continuous evaporation of the water from the reservoir. As the concentration of these salts increases, they begin to precipitate, forming a crust at the water edge and on the evaporating surfaces.- This crust hinders the functioning of the wicklike member and inhibits its ability to speed evaporation of moisture into the air.

Several methods have been attempted to prevent the precipitation of these hard water salts. Automatic pumps have been attached to the humidifier reservoir for changing the water at regular intervals. These pumps do not solve the problem because they do not prevent the precipitation of salts on the evaporating surfaces. Attempts have been made to use salts in the solution that are precipitated by the calcium and magnesium ions in hard water. This method has proved unsatisfactory because most salts do not combine with a sufficient number of such ions to make them practical. Furthermore, the precipitate from this method accumulates on the plastic evaporating pads and reduces their efficiency. Attempts have been made to use sequestering agents but these have not proved successful because they must be in high concentration in order to hold the hard water salts in solution. Even when these sequestering agents are used, an appreciable amount of salts still precipitates on the edge of the water and on the evaporating surface of the wicklike member.

This invention contemplates the addition of nonionic surfactants and a preservative to the water within the reservoir. These surfactants prevent the precipitation of hard water salts at the edge of the water and on the evaporating surfaces.

Among the several objects of the present invention may be noted the provision of a method and means for humidifying a vapor wherein hard water salts will be maintained in solution in the reservoir; the provision of a method and means for humidifying which will prevent the precipitation of hard water salts on the evaporative surfaces of the wick or pad of the humidifier; the provision of a method and means for humidifying which prevents the precipitation ofhard water salts without adding a high concentration of surfactant; the provision of a method and means for humidifying wherein the useful life of the wicklike member is longer than in previous devices; and

the provision of a method and means for humidifying which is economical and convenient to use. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the products and methods hereinafter described, the scope of the invention being indicated in the following claims.

In order for the use of a surfactant to be practical, it is essential that the surfactant be effective at low concentrations so that the evaporation of the water from the reservoir and from the evaporative surfaces is not inhibited. A series of nonionic surfactants are condensation products of polyoxypropylene glycol condensed with ethylene oxide to form a molecule consisting of a hydrophobic polyoxypropylene portion and a hydrophilic polyoxyethylene portion. Certain of these, which are marketed by Wyandotte Chemical Corporation under the trademark Pluronics, have been found to be useful in carrying out the present invention.

Four examples of these compounds which can be used effectively in the method and means of this invention are:

AGENT A Agent A contains a polyoxypropylene hydrophobic base having a molecular weight ranging from 1,501 to 1,800 and a polyoxyethylene hydrophilic portion which is approximately percent by weight of the total molecule.

AGENT B Agent B contains a polyoxypropylene hydrophobic base having a molecular weight ranging from 2,101 to 2,500 and a polyoxyethylene hydrophilic portion which is approximately 80 percent by weight of the total molecule.

AGENT C Agent C contains a polyoxypropylene hydrophobic base having a molecular weight ranging from 1,501 to 1,800 and a polyoxyethylene hydrophilic portion which is approximately 40 percent by weight of the total molecule.

AGENT D Agent D contains a polyoxypropylene hydrophobic base having a molecular weight ranging from 1,501 to 1,800 and a polyoxyethylene hydrophilic portion which is approximately 20 percent by weight of the total molecule.

When these agents are added to the water in the reservoir of a humidifier they prevent the forming of hard water salt precipitates around the edge of the water and on the evaporative pads of the humidifier. The plastic evaporative pads remain soft and pliable for a longer period of time than in previously known humidifiers. While all four of these agents produce satisfactory results when dissolved in the reservoir of a humidifier, Agent A and Agent B are preferred.

The following examples illustrate the invention.

EXAMPLE 1 A preparatory solution is provided from the following components:

By weight Agent A 5 to 30% Formaldehyde (37% solution) Approximately 1% Water 69 to 94% This preparatory solution is added to the water in the humidifier reservoir at the ratio of 1 ounce preparatory solution to one-half gallon of water in the reservoir.

EXAMPLE 2 A preparatory solution is provided from the following components:

By weight Agent 8 S to 30% Formaldehyde (37% solution) Approximately 1% Water 69 to 94% This preparatory solution is added to the water in the humidifier reservoir at the ratioof 1 ounce preparatory solution to one-half gallon of water in the reservoir.

The formaldehyde in Examples 1 and 2 acts as a preservative to prevent the growth of bacteria within the reservoir. While formaldehyde has been found to be preferable for this purpose, other preservatives may be used without detracting from the invention.

When Agent A or Agent B is used as set forth in Examples 1 and 2 it will maintain at least 4,000 p.p.m. of CaCO in suspension in the reservoir. During extended use the evaporation pad will remain soft and efficient without the formation of any crust of hard water salts thereon. After the humidifier has been in operation for a period of time, the concentration of hard water salts in the solution increases. When the concentration of salts reaches such a level that it inhibits evaporation of the water into the atmosphere or other surrounding vapor, the solution is replaced with a fresh solution. The preferred time for replacing the solution is when the concentration of hard water salts reaches 4,000 p.p.m. This usually occurs after a period of approximately 2 weeks of continuous use of the humidifier.

With these nonionic surfactants in solution in the reservoir, the efficiency of the humidifier remains substantially constant during extended operation of the humidifier. In addition, the useful life of the evaporative pads is greatly increased. In previous devices the evaporative pads required replacement several times during a heating season whereas with the use of this invention they remain soft and operative over a period of several heating seasons.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above methods and products without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A preparatory solution for addition to the water within the reservoir of a humidifier having a reservoir containing water and an evaporative wicklike member partially submerged in the water consisting essentially of between 69 and 94 percent by weight of water, approximately 1 percent by weight of preservative for inhibiting the growth of organisms within said reservoir, and between 5 percent and 30 percent by weight of a condensation product of polyoxypropylene glycol condensed with ethylene oxide to form a molecule having (A) a polyoxypropylene portion and (B) a polyoxyethylene portion; the ratio of the molecular weight of (A) to the percentage by weight of (B) in the total molecule being one from the group consisting of l,501l,800:80, 2,l0l-2,500:80, 1,50l l,800:40, and 1,50l-l,800:20.

2. The preparatory solution of claim 1 wherein said preservative is formaldehyde.

3. A process for humidifying a vapor comprising filling the reservoir of a humidifier with water, said humidifier being provided with an evaporative member partially within the water which acts as a wick for speeding the evaporation of water into the vapor; and adding a preparatory solution to the water in said reservoir; said preparatory solution containing between 5 percent and 30 percent by weight of a condensation product of polyoxypropylene glycol condensed with ethylene oxide to form a molecule having (A) a polyoxypropylene portion and (B) a polyoxyethylene portion; the ratio of the molecular weight of (A) to the percentage by weight of (B) in the total molecule being one from the group consisting of l,50l-l,800:80, 2,10l-2,500:80, l,50ll,800:40, and 1,501-l,800:20.

4. The process of claim 3 including adding a preservative to said preparatory solution before the addition of said preparatory solution to said water in said reservoir.

5. The process of claim 3 wherein approximately 1 ounce of preparatory solution is added to each one-half gallon of water in said reservoir.

6. The process of claim 3 including moving said evaporative member within said reservoir so as to further speed the evaporation of water into the vapor.

7. The process of claim 3 including replacing the water and preparatory solution within said reservoir whenever the concentration of hard water salts in said reservoir reaches a concentration of approximately 4,000 parts per million.

F t 10K 

2. The preparatory solution of claim 1 wherein said preservative is formaldehyde.
 3. A process for humidifying a vapor comprising filling the reservoir of a humidifier with water, said humidifier being provided with an evaporative member partially within the water which acts as a wick for speeding the evaporation of water into the vapor; and adding a preparatory solution to the water in said reservoir; said preparatory solution containing between 5 percent and 30 percent by weight of a condensation product of polyoxypropylene glycol condensed with ethylene oxide to form a molecule having (A) a polyoxypropylene portion and (B) a polyoxyethylene portion; the ratio of the molecular weight of (A) to the percentage by weight of (B) in the total molecule being one from the group consisting of 1,501-1,800:80, 2,101-2,500:80, 1,501-1,800:40, and 1,501-1,800:20.
 4. The process of claim 3 including adding a preservative to said preparatory solution before the addition of said preparatory solution to said water in said reservoir.
 5. The process of claim 3 wherein approximately 1 ounce of preparatory solution is added to each one-half gallon of water in said reservoir.
 6. The process of claim 3 including moving said evaporative member within said reservoir so as to further speed the evaporation of water into the vapor.
 7. The process of claim 3 including replacing the water and preparatory solution within said reservoir whenever the concentration of hard water salts in said reservoir reaches a concentration of approximately 4,000 parts per million. 